platform/x86: serial-multi-instantiate: Reorganize I2C functions

Reorganize I2C functions to accommodate SPI support
Split the probe and factor out parts of the code
that will be used in the SPI support
Also switched from strlcpy() to strscpy()

Signed-off-by: Lucas Tanure <tanureal@opensource.cirrus.com>
Signed-off-by: Stefan Binding <sbinding@opensource.cirrus.com>
Link: https://lore.kernel.org/r/20220121172431.6876-7-sbinding@opensource.cirrus.com
Reviewed-by: Hans de Goede <hdegoede@redhat.com>
Signed-off-by: Hans de Goede <hdegoede@redhat.com>

drivers/platform/x86/serial-multi-instantiate.c

@@ -29,96 +29,132 @@ struct smi_instance {
 
 struct smi {
 	int i2c_num;
-	struct i2c_client *i2c_devs[];
+	struct i2c_client **i2c_devs;
 };
 
-static int smi_probe(struct platform_device *pdev)
+static int smi_get_irq(struct platform_device *pdev, struct acpi_device *adev,
+		       const struct smi_instance *inst)
+{
+	int ret;
+
+	switch (inst->flags & IRQ_RESOURCE_TYPE) {
+	case IRQ_RESOURCE_GPIO:
+		ret = acpi_dev_gpio_irq_get(adev, inst->irq_idx);
+		break;
+	case IRQ_RESOURCE_APIC:
+		ret = platform_get_irq(pdev, inst->irq_idx);
+		break;
+	default:
+		return 0;
+	}
+
+	if (ret < 0)
+		dev_err_probe(&pdev->dev, ret, "Error requesting irq at index %d: %d\n",
+			      inst->irq_idx, ret);
+
+	return ret;
+}
+
+static void smi_devs_unregister(struct smi *smi)
+{
+	while (smi->i2c_num > 0)
+		i2c_unregister_device(smi->i2c_devs[--smi->i2c_num]);
+}
+
+/**
+ * smi_i2c_probe - Instantiate multiple I2C devices from inst array
+ * @pdev:	Platform device
+ * @adev:	ACPI device
+ * @smi:	Internal struct for Serial multi instantiate driver
+ * @inst_array:	Array of instances to probe
+ *
+ * Returns the number of I2C devices instantiate, Zero if none is found or a negative error code.
+ */
+static int smi_i2c_probe(struct platform_device *pdev, struct acpi_device *adev, struct smi *smi,
+			 const struct smi_instance *inst_array)
 {
 	struct i2c_board_info board_info = {};
-	const struct smi_instance *inst;
 	struct device *dev = &pdev->dev;
-	struct acpi_device *adev;
-	struct smi *smi;
 	char name[32];
-	int i, ret;
+	int i, ret, count;
 
-	inst = device_get_match_data(dev);
-	if (!inst) {
-		dev_err(dev, "Error ACPI match data is missing\n");
-		return -ENODEV;
-	}
-
-	adev = ACPI_COMPANION(dev);
-
-	/* Count number of clients to instantiate */
 	ret = i2c_acpi_client_count(adev);
 	if (ret < 0)
 		return ret;
+	else if (!ret)
+		return -ENODEV;
 
-	smi = devm_kmalloc(dev, struct_size(smi, i2c_devs, ret), GFP_KERNEL);
-	if (!smi)
-		return -ENOMEM;
+	count = ret;
 
-	smi->i2c_num = ret;
+	smi->i2c_devs = devm_kcalloc(dev, count, sizeof(*smi->i2c_devs), GFP_KERNEL);
+	if (!smi->i2c_devs)
+		return -ENOMEM;
 
-	for (i = 0; i < smi->i2c_num && inst[i].type; i++) {
+	for (i = 0; i < count && inst_array[i].type; i++) {
 		memset(&board_info, 0, sizeof(board_info));
-		strlcpy(board_info.type, inst[i].type, I2C_NAME_SIZE);
-		snprintf(name, sizeof(name), "%s-%s.%d", dev_name(dev), inst[i].type, i);
+		strscpy(board_info.type, inst_array[i].type, I2C_NAME_SIZE);
+		snprintf(name, sizeof(name), "%s-%s.%d", dev_name(dev), inst_array[i].type, i);
 		board_info.dev_name = name;
-		switch (inst[i].flags & IRQ_RESOURCE_TYPE) {
-		case IRQ_RESOURCE_GPIO:
-			ret = acpi_dev_gpio_irq_get(adev, inst[i].irq_idx);
-			if (ret < 0) {
-				dev_err(dev, "Error requesting irq at index %d: %d\n",
-						inst[i].irq_idx, ret);
-				goto error;
-			}
-			board_info.irq = ret;
-			break;
-		case IRQ_RESOURCE_APIC:
-			ret = platform_get_irq(pdev, inst[i].irq_idx);
-			if (ret < 0) {
-				dev_dbg(dev, "Error requesting irq at index %d: %d\n",
-					inst[i].irq_idx, ret);
-				goto error;
-			}
-			board_info.irq = ret;
-			break;
-		default:
-			board_info.irq = 0;
-			break;
-		}
+
+		ret = smi_get_irq(pdev, adev, &inst_array[i]);
+		if (ret < 0)
+			goto error;
+		board_info.irq = ret;
+
 		smi->i2c_devs[i] = i2c_acpi_new_device(dev, i, &board_info);
 		if (IS_ERR(smi->i2c_devs[i])) {
 			ret = dev_err_probe(dev, PTR_ERR(smi->i2c_devs[i]),
 					    "Error creating i2c-client, idx %d\n", i);
 			goto error;
 		}
+		smi->i2c_num++;
 	}
-	if (i < smi->i2c_num) {
-		dev_err(dev, "Error finding driver, idx %d\n", i);
+	if (smi->i2c_num < count) {
+		dev_dbg(dev, "Error finding driver, idx %d\n", i);
 		ret = -ENODEV;
 		goto error;
 	}
 
-	platform_set_drvdata(pdev, smi);
-	return 0;
+	dev_info(dev, "Instantiated %d I2C devices.\n", smi->i2c_num);
 
+	return 0;
 error:
-	while (--i >= 0)
-		i2c_unregister_device(smi->i2c_devs[i]);
+	smi_devs_unregister(smi);
 
 	return ret;
 }
 
+static int smi_probe(struct platform_device *pdev)
+{
+	const struct smi_instance *inst_array;
+	struct device *dev = &pdev->dev;
+	struct acpi_device *adev;
+	struct smi *smi;
+
+	adev = ACPI_COMPANION(dev);
+	if (!adev)
+		return -ENODEV;
+
+	inst_array = device_get_match_data(dev);
+	if (!inst_array) {
+		dev_dbg(dev, "Error ACPI match data is missing\n");
+		return -ENODEV;
+	}
+
+	smi = devm_kzalloc(dev, sizeof(*smi), GFP_KERNEL);
+	if (!smi)
+		return -ENOMEM;
+
+	platform_set_drvdata(pdev, smi);
+
+	return smi_i2c_probe(pdev, adev, smi, inst_array);
+}
+
 static int smi_remove(struct platform_device *pdev)
 {
 	struct smi *smi = platform_get_drvdata(pdev);
-	int i;
 
-	for (i = 0; i < smi->i2c_num; i++)
-		i2c_unregister_device(smi->i2c_devs[i]);
+	smi_devs_unregister(smi);
 
 	return 0;
 }